Looking for a bpcr or other lower pressure single shot rolling block capable application for a .318 Mauser J barrel, new, minty.

A paper patch application is ok. I can see a 314 or 313 patched up working but I need a cartridge base to work from. I checked Steves pages obsoletes and didn't find a good US match.
Need someone who has "thunk" out of the box.

Brass fabrication is OK! Rimmed better than other options, from current production brass like a 30-30 would be nice. I'll figure out dies later, I'll bastardize old dies as needed to create initial form dies

Anything stand out for anyone?

Thank in advance.

Marlene, I have an esoteric Mauser target rifle, anshutz, in 8.15, have dies but not attempted to chamber cast, form brass, etc.

I had not considered the euro obsolete list. That would be ideal and the twist should be complaint with a 200 gr cast bullet.

That is an excellent idea and......... I can form from 30-30, win win!

Thank you!

I have enough 7x57R brass to share, if that helps your thinking.